Find all references does not find all references

### Your environment

#### Which OS do you use?

Ubuntu 20.04

#### Which version of GHC do you use and how did you install it?

GHC 9.2.3

#### How is your project built (alternative: link to the project)?

Nix+bazel

#### Which LSP client (editor/plugin) do you use?

We're using `VSCode` with the `Haskell` plugin

### Steps to reproduce

In any project, "Find all references" does not reference files that have not been indexed by HLS.
From what we've empirically inferred, it seems that HLS only lists the references appearing in already indexed files and indexing is lazy. Files that have never been indexed (because they're leaves of the dependency tree and have never been opened in the editor) are off the radar.
After opening said files, "Find all references" does list all the references. This kind of defeats the purpose of the feature since one has first to `Ctrl-Shift-F` the function of interest, open the search hits in the editor and then use the "Find all references".
The fact that one cannot "trust" the result of "Find all references" because it depends on the history of opened files in the editor is a problem. It would be more accurate to call the feature "Find some references (warning: lazy search)" or something similar.

### Expected behaviour

One would expect "Find all references" to find all references

### Actual behaviour

"Find all references" does not find all references.